CVE-2026-31630: Linux kernel · rxrpc: proc: size address buffers for %pISpc output
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 7.8 High · fixed in db297c78ce537c9ac96f0eda9b25ad72c8caefa9 : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:18 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in db297c78ce537c9ac96f0eda9b25ad72c8caefa9, a6042b8066b24dbcc7945616a157d4d43e463668, a44ce6aa2efb61fe44f2cfab72bb01544bbca272 +5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 24 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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Description
In the Linux kernel, the following vulnerability has been resolved: rxrpc: proc: size address buffers for %pISpc output The AF_RXRPC procfs helpers format local and remote socket addresses into fixed 50-byte stack buffers with "%pISpc". That is too small for the longest current-tree IPv6-with-port form the formatter can produce. In lib/vsprintf.c, the compressed IPv6 path uses a dotted-quad tail not only for v4mapped addresses, but also for ISATAP addresses via ipv6_addr_is_isatap(). As a result, a case such as [ffff:ffff:ffff:ffff:0:5efe:255.255.255.255]:65535 is possible with the current formatter. That is 50 visible characters, so 51 bytes including the trailing NUL, which does not fit in the existing char[50] buffers used by net/rxrpc/proc.c. Size the buffers from the formatter's maximum textual form and switch the call sites to scnprintf(). Changes since v1: - correct the changelog to cite the actual maximum current-tree case explicitly - frame the proof around the ISATAP formatting path instead of the earlier mapped-v4 example
References
- git.kernel.org/stable/c/386c86412608d3449006a318a662cbcd6ca1f668 (opens in a new tab)
- git.kernel.org/stable/c/235b2115de892eab2e107a42efa7a4347baaa80b (opens in a new tab)
- git.kernel.org/stable/c/625af53a1564e31bb2df9adc3739df46137f46c1 (opens in a new tab)
- git.kernel.org/stable/c/808a34cdbe8ce336c202d8ea6d5e48496764dc37 (opens in a new tab)
- git.kernel.org/stable/c/a6042b8066b24dbcc7945616a157d4d43e463668 (opens in a new tab)
- git.kernel.org/stable/c/db297c78ce537c9ac96f0eda9b25ad72c8caefa9 (opens in a new tab)
- git.kernel.org/stable/c/10ebed83f9f6414af4e85bc85ffaeda7effdd874 (opens in a new tab)
- git.kernel.org/stable/c/a44ce6aa2efb61fe44f2cfab72bb01544bbca272 (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-784472.html (opens in a new tab)